Surface micromachined microneedles

Abstract

Surface micro-machined micro-needles ( 32 ) are formed as single needles ( 32 ) or in two-dimensional or three-dimensional micro-needle arrays ( 30 ). The micro-needles ( 32 ) are fabricated on a substrate ( 12 ) which can remain attached to the micro-needles ( 32 ) or can be subsequently removed. The two-dimensional or three-dimensional micro-needle arrays ( 30 ) can have cross-coupling flow channels ( 36 ) which allow for pressure equalization, and balance of fluid flow within the micro-needle arrays ( 30 ). Each of the micro-needles ( 32 ) has a micro-channel ( 36 ) therethrough that provides communication between at least one input port ( 37 ) at a proximal end of the micro-needles ( 32 ), and at least on output port ( 39 ) at an opposite distal end.

1. A microneedle array device, comprising:
 a substrate having a substantially planar first surface and an edge adjacent said substantially planar first surface; and 
 a plurality of hollow non-silicon microneedles positioned on said substantially planar first surface of said substrate, each of said hollow non-silicon microneedles having a microchannel therethrough providing communication between at least one input port at a proximal end of each of said hollow non-silicon microneedles and at least one output port at a distal end of each of said hollow non-silicon microneedles, wherein said hollow non-silicon microneedles extend beyond said edge of said substrate and extend in a direction substantially parallel to said substantially planar first surface. 
 
     
     
       2. The microneedle array device of  claim 1 , wherein said hollow non-silicon microneedles each have a bottom wall, two side walls, and a top wall defining a microchannel. 
     
     
       3. The microneedle array device of  claim 2 , wherein said bottom wall is formed at least partially on top of said substantially planar first surface of said substrate and said side walls and top wall are formed around a removable molding material. 
     
     
       4. The microneedle array device of  claim 1 , wherein said hollow non-silicon microneedles comprise a two dimensional array. 
     
     
       5. The microneedle array device of  claim 1 , wherein said hollow non-silicon microneedles comprise a three dimensional array. 
     
     
       6. The microneedle array device of  claim 5 , wherein said three dimensional array comprises a plurality of two dimensional arrays with spacers therebetween. 
     
     
       7. The microneedle array device of  claim 6 , wherein said three dimensional array is bonded together by a material selected from the group consisting of molding materials, polymeric adhesives, and combinations thereof. 
     
     
       8. The microneedle array device of  claim 1 , wherein said hollow non-silicon microneedles are aligned substantially parallel to each other on said substrate. 
     
     
       9. The microneedle array device of  claim 1 , wherein the distal end of each said hollow non-silicon microneedle extends beyond said edge of said substrate a distance from about 10 μm to about 100 mm. 
     
     
       10. The microneedle array device of  claim 1 , wherein said microchannel in each of said hollow non-silicon microneedles has a cross-sectional area in the range from about 25 μm 2  to about 5000 μm 2 . 
     
     
       11. The microneedle array device of  claim 1 , wherein the length of each said hollow non-silicon microneedle is from about 0.05 μm to about 5 mm, and the width of each said hollow non-silicon microneedle is from about 0.05 μm to about 1 mm. 
     
     
       12. The microneedle array device of  claim 1 , wherein the center-to-center spacing between individual said hollow non-silicon microneedles is from about 50 μm to about 200 μm. 
     
     
       13. The microneedle array device of  claim 1 , wherein said substrate comprises a material selected from the group consisting of glass, semiconductor materials, metals, ceramics, plastics, and composites or combinations thereof. 
     
     
       14. The microneedle array device of  claim 1 , wherein said hollow non-silicon microneedles comprise a material selected from the group consisting of metals, plastics, ceramics, glass, carbon black, and composites or combinations thereof. 
     
     
       15. The microneedle array device of  claim 1 , wherein said hollow non-silicon microneedles comprise a metal material selected from the group consisting of nickel, copper, gold, palladium, titanium, chromium, and alloys or combinations thereof. 
     
     
       16. The microneedle array device of  claim 1 , wherein said hollow non-silicon microneedles can withstand flow rates of up to about 1.5 cc/sec. 
     
     
       17. The microneedle array device of  claim 1 , further comprising a coupling channel member providing fluid communication between said hollow non-silicon microneedles. 
     
     
       18. The microneedle array device of  claim 17 , wherein said coupling channel member is composed of the same material as said hollow non-silicon microneedles. 
     
     
       19. The microneedle array device of  claim 1 , further comprising a pair of structural support members mechanically interconnecting said hollow non-silicon microneedles and precisely controlling penetration depth of said hollow non-silicon microneedles. 
     
     
       20. The microneedle array device of  claim 1 , wherein said hollow non-silicon microneedles have a plurality of input ports. 
     
     
       21. The microneedle array device of  claim 1 , wherein said hollow non-silicon microneedles have a plurality of output ports. 
     
     
       22. A microneedle device, comprising:
 a substrate having a substantially planar first surface and an edge adjacent said substantially planar first surface; and 
 a single hollow non-silicon microneedle positioned on said substantially planar first surface of substrate, said hollow non-silicon microneedle having at least one microchannel therethrough providing communication between at least one input port at a proximal end of said hollow non-silicon microneedle and at least one output port at distal end of said hollow non-silicon microneedle, the distal end of said hollow non-silicon microneedle extending beyond said edge of said substrate, wherein said hollow non-silicon microneedle extends in a direction substantially parallel to said substantially parallel first surface. 
 
     
     
       23. The microneedle device of  claim 22 , wherein the distal end of said hollow non-silicon microneedle extends beyond said edge of said substrate a distance from about 10 μm to about 100 mm. 
     
     
       24. The microneedle device of  claim 22 , wherein said microchannel in said hollow non-silicon microneedle has a cross-sectional area in the range from about 25 μm 2  to about 5000 μm 2 . 
     
     
       25. The microneedle device of  claim 22 , wherein said substrate comprises a material selected from the group consisting of glass, semiconductor materials, metals, ceramics, plastics, and composites or combinations thereof. 
     
     
       26. The microneedle device of  claim 22 , wherein said hollow non-silicon microneedle comprises a metal material selected from the group consisting of nickel, copper, gold, palladium, titanium, chromium, and alloys or combinations thereof. 
     
     
       27. The microneedle device of  claim 22 , wherein the distal end has a plurality of output ports. 
     
     
       28. The microneedle device of  claim 22 , further comprising a structural support to control penetration depth. 
     
     
       29. The microneedle device of  claim 28 , wherein said structural support is adapted to mechanically fix the microneedle device to a surface that is penetrated by said hollow non-silicon microneedle. 
     
     
       30. A method of fabricating a microneedle, comprising:
 providing a substrate with a substantially planar first surface; 
 depositing a metal material on said substantially planar first surface to form one or more bottom walls for one or more microneedles; 
 coating a top surface of said one or more bottom walls with a photoresist layer to a height corresponding to a selected inner height of a microchannel for said one or more microneedles; 
 depositing a metal material to form side walls and a top wall upon said one or more bottom walls and around said photoresist layer; and 
 removing said photoresist layer from said microchannel of said one or more microneedles; wherein said one or more microneedles are formed on said substantially planar first surface of said substrate and extend in a direction substantially parallel to said substantially planar first surface. 
 
     
     
       31. The method of  claim 30 , wherein the metal material is deposited by an electroplating process. 
     
     
       32. The method of  claim 30 , wherein the metal material is selected from the group consisting of palladium, titanium, chromium, nickel, gold, copper, and alloys thereof.